Epoxy resin compositions of enhanced creep resistance

ABSTRACT

A room temperature aged epoxy resin grout utilizing a mixture of the diglycidyl ether of bis-phenol A and a siliceous aggregate such as sand is markedly improved in creep deformation performance when a reactive diluent such as the diglycidyl ether of cyclohexane dimethanol and a curing agent such as triethylene tetraamine are admixed with said grout.

This invention relates to epoxy resin compositions having improved creepresistance and more particularly, to polyepoxide compositions capable ofbeing resinified at room temperature and exhibiting enhanced creepdeformation performance.

BACKGROUND OF THE INVENTION

It is widely known that use of epoxy resins for many applications isprompted by the deformation resistance of such resins which, when curedare subjected to compressive forces and/or elevated temperatures. Epoxyresin compositions that are heat cured exhibit great resistance to andstand up well under abrasive environments as well. Such epoxycompositions utilizing particulate fillers such as silica and aluminahave been sold for the surface coating of metal pipes and cement floors,for securing equipment to said coated floors, for installation andsecuring of anchor bolts to a wide variety of surfaces, and for thegrouting of original installations of heavy equipments such as hammermills and integral gas compressors.

These large integral gas compressors consist of an internal combustionengine driving a reciprocating gas compressor. Engine powder cylindersand compressor cylinders are mounted on a common crankshaft and cylinderblock. Integral gas compressors typically operate at slow speeds,several hundred revolutions per minute, and develop several thousandhorsepower. Crankshafts are large, typically some 14 inches in diameterand 20 feet long. Minor misalignment of main journal bearings is aserious operational problem. Integral gas compressors are typicallyinstalled on a concrete foundation block covered by a layer of aggregatefilled epoxy grout. The epoxy grout aids in alignment and securemounting and protects the concrete foundation from chemical attack. Someintegral gas compressors suffer from gradual misalignment of thecrankshaft main bearings which is detected by web deflectionmeasurements. Limitations on web deflections to protect crankshafts,rods and bearings require that the compressor be realigned if theselimits are exceeded. This often necessitates replacement of the epoxygrout at significant cost and loss of production due to down time. Manyreasons have been suspected for the misalignment problem including somecreep, shrinkage or thermal strain of the concrete foundation, creep ofthe compressor frame, or nonuniform creep of the epoxy grout due tononuniformity of stress and temperature fields. Of these, creep of epoxygrout is studied here. Epoxy grouts consisting of resin, hardener and anaggregate filler system including sand, silane modified silica andalumina are marketed by numerous firms for use in mounting a widevariety of heavy equipment including gas compressor.

The use of silanes in resinous compositions to enhance various physicalproperties of an aggregate filled resinous product is widespread.Representative discussions of said uses include: U.S. Pat. No. 3,234,159wherein acid-resistant cements (mortars) of improved tensile strengthand very high electrical resistivity comprise silica sand containing aminor amount of phenol formaldehyde resin solids containing up to 10% ofan amino functional silane;

U.S. Pat. No. 3,328,339 wherein a reinforced polymeric composition isimproved in its physical properties such as increased flexural strengthand modulus by reacting an organosilane coupling agent with the silanemonomer prior to polymerization and thereafter chemically binding theresulting polymer to a siliceous mineral reinforcing agent;

U.S. Pat. No. 3,390,120 wherein the modulus and tear resistance ofpolyurethane polymer compositions are said to be enhanced by a kaolinclay modified by from 1 to 3% of an amino organosilane;

U.S. patent application Ser. No. 333,675 filed Dec. 23, 1981, nowabandoned (of common assignee) wherein it is taught that amino silanetreated siliceous aggregate can be utilized as an additive to epoxycompositions to markedly increase its chemical and temperatureresistance while retaining the useful workability and abrasionresistance of said compositions.

It is an object of this invention to provide an epoxy resin compositionof enhanced resistance to creep deformation while retaining itsresistance to adverse chemical and/or elevated temperature environmentswhile retaining its resistance to abrasion.

SUMMARY OF THE INVENTION

It has been discovered that the combination of a diglycidyl ether ofbisphenol A with a reactive diluent as represented by the diglycidylether of cyclohexane dimethanol reacted with a converter represented bytriethylene tetraamine in the presence of a major amount of particulateaggregate results in an epoxy grout of enhanced resistance to creepdeformation.

In accordance with this invention there has been provided an epoxy resincomposition comprising:

(a) an epoxy resin having at least two ##STR1## groups per molecule; (b)a reactive diluent represented by the diglycidyl ether of cyclohexanedimethanol;

(c) a converter represented by triethylene tetraamine in a sufficientamount to cure said epoxy resin at about room temperature; and,

(d) a major amount of an aggregate filler having a particulate sizeranging from 5 to 400 mesh.

More particularly, this invention provides an epoxy resin comprising:

(a) an epoxy resin represented by the diglycidyl ethers of bisphenol A;

(b) reactive diluent represented by the diglycidyl ether of cyclohexanedimethanol in an amount ranging from 0.3 to 1, preferably 0.5, part byweight per weight part of said epoxy resin;

(c) at least an effective amount of triethylene tetraamine converter;and,

(d) from 4.5 to 5.5, preferably 5, parts by weight of a siliceousaggregate per part by weight of the combined weight of (a), (b) and (c).

A highly useful composition according to this invention comprises:

(a) from 10 to 20, preferably 16 to 18, weight percent of any epoxyresin diluted with about 0.5 part by weight per part by weight of saidresin of the diglycidyl ether of cyclohexane dimethanol and at least aneffective amount of triethylene tetraamine to cure said epoxy resin atabout room temperature; and,

(b) from 80 to 90 parts by weight of a siliceous aggregate having aparticulate size ranging from 8 to 400 mesh; with from 20 to 30,preferably 25, weight percent of siliceous aggregate having aparticulate size ranging from 100 to 400 mesh, said weight percent beingbased on the total weight of said composition.

DETAILED DESCRIPTION OF THE INVENTION Epoxy Resin

The resinous epoxides suitable for use in the present invention comprisethose compounds having at least two epoxy groups, i.e., at least two##STR2## groups per molecule. The polyepoxides may be saturated orunsaturated, cycloaliphatic, aromatic, heterocyclic or preferablyaliphatic, and, may be substituted, if desired, with substituents suchas chlorine atoms, hydroxyl groups, ether radicals, and the like. Theymay also be monomeric or polymeric. The epoxy may be either present as aterminal or interior group.

Preferred polyepoxides of this type are the glycidyl polyethers ofdihydric phenols produced by this method from dihydric phenols andepichlorohydrin as fully described along with a wide variety of otherpolyepoxides in U.S. Pat. No. 3,396,138.

Typical of the epoxy resins which may be employed are theepichlorohydrin-bis-phenol A type sold under the trademarks "EponResins" (Shell Chemical Corporation), "Gen Epoxy" (General Mills), "DERResins" (Dow Chemical Corporation), "Araldite" (Ciba), "ERL Resins"(Bakelite Corporation), "Epi-Rez" (Celanese Corporation), and "Epiphen"(The Borden Company).

Reactive Diluent

The reactive diluent is a low viscosity cycloaliphatic diepoxide whichwill fully react in the admixture with the epoxy resin and become a partof the cross-linked resin structure. The reactive diluent must have aviscosity ranging from 49 to 100 cps at 25° C. so that when admixed withthe epoxy resin provides a viscosity at 25° C. ranging from 500 to 1000cps. A highly suitable reactive diluent is the diglycidyl ether ofcyclohexane dimethanol with a viscosity of 60 cps at 25° C. For theadmixture, a sufficient amount of reactive diluent is provided to givethe mixture a viscosity of from 500 to 1000 cps at 25° C. which has beenfound to usually range from 3 to 1, preferably 2, parts of epoxy resinper part by weight of reactive diluent.

Converter

As the cross-linking compounds, i.e. converter for the epoxy resincompositions of the invention, an alkylene polyamine has been foundsurprisingly useful. The epoxy resin-reactive diluent-converteradmixture generally represents from 10 to 20, preferably 15 to 19,optimally 16 to 18, to 18, weight percent of the grout with the balancebeing weight percent of the grout with the balance being siliceousaggregate. With triethylene tetraamine as the converter, an effectiveamount to provoke room temperature cross linking is 1 weight part ofconverter for 8 parts of resin admixture with a ratio of 1 part ofconverter to 7.7 parts by weight of resin admixture preferred.

Silica Aggregate

The siliceous aggregate employed as filler in the present inventionwhould have an average particle size not greater than 5 mesh and mayrange in average size from 8 mesh to 500 mesh. It is preferred to employfiller having an average particle size between 8 and 400 mesh as definedby the U.S. Standard Sieve Series ASTM E-11-61. It is the filler thanenhances the physical resistance of the composition.

The siliceous aggregate includes silica sand, silane modified silica oralumina including sintered bauxite and mixtures thereof. Preferably thesiliceous aggregate contains at least 25% silica sand. Useful mixturesinclude: from 70 to 80%, preferably 75%, silica with a size of 8 mesh to100 mesh and from 20 to 30%, preferably 25%, silica flour having anominal 300 mesh particle size. The siliceous aggregate represents from80 to 90, preferably 85 to 89, optimally about 84 to 86 weight percentof the total composition. The siliceous aggregate can be treated with anamino organosilane according to the teachings of U.S. patent applicationSer. No. 333,675, filed Dec. 23, 1981, if desired, to provide at least0.5, usefully from 1 to 3, preferably 1.5 to 2.0 weight percent silanebased on the weight of the aggregate whereby the chemical andtemperature stability of the final epoxy resin grout is enhanced.

Generally, then in addition to the silica aggregate various types ofinert pigments and fillers may also be incorporated into the aggregatecompositions. As examples of such fillers may be mentioned blanc fixe,talc, pyrophyllite, diatomaecous earth, silica aerogel, and other likeinert materials.

Color materials may be added to the compositions if desired. Thecoloring materials include organic and inorganic coloring materials. Asexamples may be mentioned titanium dioxide and carbon black. Coloringmaterials should be selected, however, so as to be non-reactive with theepoxy resins and other ingredients at atmospheric temperature, asotherwise this might cause poor storage stability and also affectretention of adhesiveness and abrasion resistance.

The composition of the present invention may also have incorporatedtherein, if desired, a lubricant, such as silicone oils, silicone jelly,petroleum jellies and so forth.

The manner in which the present invention may be practiced will be clearfrom the following examples which are to be considered illustrativerather than limiting.

EXAMPLE 1

This example illustrates the preparation of an epoxy resin compositionwhich provides a non-hydraulic grouting composition of enhanced creepdeformation performance. 5 parts by weight of siliceous aggregateconsisting of 75% by weight of silica sand having a particle sizeranging from 8 mesh to 100 mesh and 25% by weight of silica flour havinga 300 mesh particle size was admixed with 1 part by weight of the epoxyresin-reactive diluent-converter admixture having a viscosity of about800 cps at 25° C. The epoxy resin admixture was 2 parts by weight ofEpon 828 (an epoxy resin consisting of the diglycidyl ether of bisphenolA) sold by the Shell Chemical Company, Houston, Tex., 1 part by weightof the reactive diluent MK-107 (the diglycidyl ether of cyclohexanedimethanol) sold by the Wilmington Chemical Corporation of Wilmington,Del.) and 0.39 parts by weight of triethylene tetraamine as theconverter. This epoxy resin thus consisted of 9.8 weight percent of thediglycidyl ether Bisphenol A, 4.9 weight percent of the diglycidyl etherof cyclohexane dimethanol, 2 weight percent of triethylene tetraamine asa converter, 62.5 weight percent of a sand aggregate having a particlesize ranging from 8 mesh to 100 mesh and 20.8 weight percent of silicaflour having a particle size of 300 mesh. The epoxy resin cure,according to the invention is realized after 24 hours (a 1 day cure) atambient temperature.

EXAMPLE 2

An additional epoxy resin composition which is essentially the same asthat produced under Example 1 but utilizing as an aggregate the silicaaggregate modified by about 1.5 wt% of amino silane resulting from thetreatment of the aggregate with sufficient A-1100 (gamma-amino propyltriethoxy silane) sold by Union Carbide Corporation of New York, N.Y.)and thereafter heating the treated siliceous aggregate at 100° C. for 24hours to dryness prior to admixture into the epoxy resin grout.

EXAMPLES 3-7

Five additional grouting compositions were prepared as in Examples 1 and2 with changes in the diluent and converter and evaluated for creepdeformation as seen from the following Table I.

                  TABLE I                                                         ______________________________________                                        CREEP DEFORMATION ANALYSIS                                                    150° Test Data                                                         Formulation                                                                                                     Creep Deformation                           Ex-                               Results                                     am-          Dilu-   Con-         × 10.sup.-6 in.sup.2 /lb at 1000      ple  Epoxy   ent     verter                                                                              Additive                                                                             hrs (165° F., 250                    ______________________________________                                                                          psi)                                        3    Epon    BGE     TETA  --     90                                               828                                                                      4    Epon    BGE     TETA  Amino* 88                                               828                   Silane                                             *1   Epon    MK107   TETA  --     18                                               828                                                                      2    Epon    MK107   TETA  Amino* 16                                               828                   Silane                                             5    Epon    BGE     Poly- Amino* 200                                              828             amide*                                                                              Silane                                             6    Epon    BGE     Poly- --     150                                              828             amide*                                                   7    Epon    MK107   Poly- Amino* 100                                              828             amide*                                                                              Silane                                             ______________________________________                                         BGE represents butyl diglycidyl ether.                                        TETA represents triethylene tetraamine                                        *Polyamide purchased from Union Camp as "UniRez 2355                          *Refers to the aminosilane treated aggregate as prepared in Example 2.   

From Table I, it is seen that the epoxy resin grouts of the invention(the grouts of Examples 1 and 2) had about a ten fold creep deformationimprovement over known systems (the grout of Example 6).

The invention in its broader aspect is not limited to the specificdetails shown and described and departures may be made from such detailswithout departing from the principles of the invention and withoutsacrificing its chief advantages.

What is claimed is:
 1. A method of filling the voids between the surfaceof a support floor and a contiguous bottom surface of a planar membersupporting heavy equipment comprising the steps of (1) grouting fullysaid voids with an epoxy resin composition comprising:(a) an epoxy resinhaving at least two ##STR3## groups per molecule; (b) a reactive diluentrepresented by the diglycidyl ether of cyclohexane dimethanol; (c) aconverter represented by triethylene tetraamine in sufficient amount tocure said epoxy resin at about room temperature; and, (d) a major amountof an aggregate having a particulate size ranging from 5 to 400 mesh;(2)curing said composition to hardness.
 2. The method according to claim 1wherein said epoxy resin is a diglycidyl ether of bisphenol A, saidreactive diluent is present in an amount ranging from 0.3 to 1 part byweight per weight part of said epoxy resin and said aggregate ranges inan amount of from 4.5 to 5.5 parts by weight of a siliceous aggregateper part by weight of the combined weight of (a), (b) and (c).
 3. Themethod according to claim 2 wherein there is 1 parts by weight of saidsiliceous aggregate per part by weight of said combined weight.
 4. Themethod according to claim 1 wherein said epoxy composition comprises(a)from 10 to 20 weight percent of said epoxy resin diluted with about 0.5part by weight per part by weight of said resin of the diglycidyl etherof cyclohexane dimethanol and at least an effective amount oftriethylene tetraamine to cure said epoxy resin at about roomtemperature; and, (b) from 80 to 90 part by weight of a siliceousaggregate having a particulate size ranging from 8 to 400 mesh with from20 to 30 weight percent of siliceous aggregate having a particulate sizeranging from 100 to 400 mesh, said weight percent being based on thetotal weight of said composition.